1. Field of the Invention
The present invention relates to a pointing device which is used as an input device for providing coordinate data of a CRT display of a computer.
2. Background Art
Conventionally, there are some kinds of pointing devices, such as a track ball, a mouse and so on, which are used as an input device to move the cursor around on a computer display. The track ball consists of a mounting which is usually in the form of a box, a ball which is set in the upper portion of the box, and one or more buttons. When the user spins the ball directly, the cursor moves at the speed and in the direction of the ball's motion. Furthermore the buttons are used for specific actions. On the other hand, the mouse consists of a box, a ball which is set thereunder, and one or more buttons. When the user moves the mouse on a flat surface, the ball rotates, and then the cursor moves at the speed and in the direction of the ball's motion. The buttons are also used for specific actions.
Recently, a pointing device having both functions of the track ball and mouse has been developed. In this pointing device, when the ball is set at the upper side thereof, it becomes a track ball. On the other hand, when the ball is set at the bottom side of the box, it becomes a mouse. However, in this pointing device, the function for switching from between the track ball to the mouse, and vice verse, is manually switched by the user.